Heat exchanger and a method for forming a heat exchanger

ABSTRACT

A heat exchanger includes a spine fin strip wrapped onto a conduit in a helical pattern. A first plurality of spine fins of the spine fin strip extends from a base of the spine fin strip, and a second plurality of spine fins of the spine fin strip is bent relative to the spine fins of the first plurality of spine fins. A related method for forming a heat exchanger is also provided.

FIELD OF THE INVENTION

The present subject matter relates generally to heat exchangers, such asheat exchangers for refrigerator appliances, and methods for formingheat exchangers.

BACKGROUND OF THE INVENTION

Refrigerator appliances generally include sealed systems for coolingchilled chambers of the refrigerator appliance. During operation of thesealed system, a compressor generates compressed refrigerant. Thecompressed refrigerant flows to a condenser where the refrigerant iscondensed into a liquid and is sent to an expansion device. Theexpansion device reduces a pressure of the refrigerant before therefrigerant enters into an evaporator as a combination of liquid andvapor. The refrigerant exits the evaporator as vapor and is transportedto the compressor via a suction line. Refrigerant within the evaporatorabsorbs heat from the chilled chambers.

Various heat exchangers are available for use in refrigeratorappliances. Certain refrigerator appliances include tube fin heatexchangers, and tube fin heat exchangers may include vortex generators.The vortex generators are typically a series of winglets mounted orpunched into the fins. The winglets form counter-rotating longitudinalair vortices in a flow path direction of the refrigerant that increasesair mixing and thus improves heat transfer. However, tube fin heatexchangers can be expensive relative to alternative heat exchangers.

Spine fin heat exchangers include spine fin coils wrapped about aconduit. The spine fin coils can facilitate heat transfer betweenrefrigerant within the conduit and ambient atmosphere about the spinefin heat exchanger. Spine fin heat exchangers are generally lessexpensive than comparable tube fin heat exchangers.

Accordingly, a spine fin heat exchanger with vortex generators would beuseful. In particular, a spine fin heat exchanger with features forgenerating counter-rotating longitudinal air vortices in a flow pathdirection of refrigerant within the heat exchanger to increase airmixing and improve heat transfer would be useful.

BRIEF DESCRIPTION OF THE INVENTION

The present subject matter provides a heat exchanger with a spine finstrip wrapped onto a conduit in a helical pattern. A first plurality ofspine fins of the spine fin strip extends from a base of the spine finstrip, and a second plurality of spine fins of the spine fin strip isbent relative to the spine fins of the first plurality of spine fins. Arelated method for forming a heat exchanger is also provided. Additionalaspects and advantages of the invention will be set forth in part in thefollowing description, or may be apparent from the description, or maybe learned through practice of the invention.

In a first exemplary embodiment, a method for forming a heat exchangeris provided. The method includes cutting a plurality of spine fins intoa sheet of metal, bending a subset of the plurality of spine fins,folding the sheet of metal to form a spine fin strip such that theplurality of spine fins extend from a base of the spine fin strip, andwrapping the spine fin strip onto a conduit in a helical pattern at anouter surface of the conduit such that the plurality of spine finsincludes spine fins that extend radially away from the outer surface ofthe conduit and also includes spine fins that are bent relative to theradially extending spine fins.

In a second exemplary embodiment, a heat exchanger is provided. The heatexchanger includes a conduit having an outer surface. A spine fin stripis wrapped onto the conduit in a helical pattern at the outer surface ofthe conduit. The spine fin strip includes a base positioned at the outersurface of the conduit. A first plurality of spine fins extends radiallyfrom the base and away from the outer surface of the conduit. A secondplurality of spine fins is bent relative to the spine fins of the firstplurality of spine fins. The base, the spine fins of the first pluralityof spine fins and the spine fins of the first plurality of spine finsare formed from a common piece of sheet metal.

In a third exemplary embodiment, a heat exchanger is provided. The heatexchanger includes a conduit having an outer surface. A spine fin stripis wrapped onto the conduit in a helical pattern at the outer surface ofthe conduit. The spine fin strip includes a base positioned at the outersurface of the conduit. A first plurality of spine fins is mounted tothe base. Each spine fin of the first plurality of spine fins defines anangle, α, with the outer surface of the conduit proximate the firstplurality of spine fins. α is about ninety degrees. A second pluralityof spine fins is mounted to the base. Each spine fin of the secondplurality of spine fins defines an angle, β, with the outer surface ofthe conduit proximate the second plurality of spine fins. β is nogreater than seventy degrees. The base, the spine fins of the firstplurality of spine fins and the spine fins of the first plurality ofspine fins are formed from a common piece of sheet metal.

These and other features, aspects and advantages of the presentinvention will become better understood with reference to the followingdescription and appended claims. The accompanying drawings, which areincorporated in and constitute a part of this specification, illustrateembodiments of the invention and, together with the description, serveto explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including thebest mode thereof, directed to one of ordinary skill in the art, is setforth in the specification, which makes reference to the appendedfigures.

FIG. 1 is a front elevation view of a refrigerator appliance accordingto an exemplary embodiment of the present subject matter.

FIG. 2 is schematic view of certain components of the exemplaryrefrigerator appliance of FIG. 1.

FIGS. 3, 4, 5, 6, 7, 8 and 9 illustrate a spine fin assembly accordingto an exemplary embodiment of the present subject matter in variousstages of formation.

FIG. 10 provides a section view of a heat exchanger according to anexemplary embodiment of the present subject matter.

DETAILED DESCRIPTION

Reference now will be made in detail to embodiments of the invention,one or more examples of which are illustrated in the drawings. Eachexample is provided by way of explanation of the invention, notlimitation of the invention. In fact, it will be apparent to thoseskilled in the art that various modifications and variations can be madein the present invention without departing from the scope or spirit ofthe invention. For instance, features illustrated or described as partof one embodiment can be used with another embodiment to yield a stillfurther embodiment. Thus, it is intended that the present inventioncovers such modifications and variations as come within the scope of theappended claims and their equivalents.

FIG. 1 depicts a refrigerator appliance 10 that incorporates a sealedrefrigeration system 60 (FIG. 2). It should be appreciated that the term“refrigerator appliance” is used in a generic sense herein to encompassany manner of refrigeration appliance, such as a freezer,refrigerator/freezer combination, and any style or model of conventionalrefrigerator. In addition, it should be understood that the presentsubject matter is not limited to use in appliances. Thus, the presentsubject matter may be used for any other suitable purpose, such as inHVAC units.

In the exemplary embodiment shown in FIG. 1, the refrigerator appliance10 is depicted as an upright refrigerator having a cabinet or casing 12that defines a number of internal chilled storage compartments. Inparticular, refrigerator appliance 10 includes upper fresh-foodcompartments 14 having doors 16 and lower freezer compartment 18 havingupper drawer 20 and lower drawer 22. The drawers 20 and 22 are“pull-out” drawers in that they can be manually moved into and out ofthe freezer compartment 18 on suitable slide mechanisms.

FIG. 2 is a schematic view of certain components of refrigeratorappliance 10, including a sealed refrigeration system 60 of refrigeratorappliance 10. A machinery compartment 62 contains components forexecuting a known vapor compression cycle for cooling air. Thecomponents include a compressor 64, a condenser 66, an expansion device68, and an evaporator 70 connected in series and charged with arefrigerant. As will be understood by those skilled in the art,refrigeration system 60 may include additional components, e.g., atleast one additional evaporator, compressor, expansion device, and/orcondenser. As an example, refrigeration system 60 may include twoevaporators.

Within refrigeration system 60, refrigerant flows into compressor 64,which operates to increase the pressure of the refrigerant. Thiscompression of the refrigerant raises its temperature, which is loweredby passing the refrigerant through condenser 66. Within condenser 66,heat exchange with ambient air takes place so as to cool therefrigerant. A condenser fan 72 is used to pull air across condenser 66,as illustrated by arrows A_(C), so as to provide forced convection for amore rapid and efficient heat exchange between the refrigerant withincondenser 66 and the ambient air. Thus, as will be understood by thoseskilled in the art, increasing air flow across condenser 66 can, e.g.,increase the efficiency of condenser 66 by improving cooling of therefrigerant contained therein.

An expansion device (e.g., a valve, capillary tube, or other restrictiondevice) 68 receives refrigerant from condenser 66. From expansion device68, the refrigerant enters evaporator 70. Upon exiting expansion device68 and entering evaporator 70, the refrigerant drops in pressure. Due tothe pressure drop and/or phase change of the refrigerant, evaporator 70is cool relative to compartments 14 and 18 of refrigerator appliance 10.As such, cooled air is produced and refrigerates compartments 14 and 18of refrigerator appliance 10. Thus, evaporator 70 is a type of heatexchanger which transfers heat from air passing over evaporator 70 torefrigerant flowing through evaporator 70. An evaporator fan 74 is usedto pull air across evaporator 70 and circulated air within compartments14 and 18 of refrigerator appliance 10.

Collectively, the vapor compression cycle components in a refrigerationcircuit, associated fans, and associated compartments are sometimesreferred to as a sealed refrigeration system operable to force cold airthrough compartments 14, 18 (FIG. 1). The refrigeration system 60depicted in FIG. 2 is provided by way of example only. Thus, it iswithin the scope of the present subject matter for other configurationsof the refrigeration system to be used as well.

FIG. 10 provides a section view of a heat exchanger 100 according to anexemplary embodiment of the present subject matter. Heat exchanger 100may be used in any suitable refrigeration system or HVAC system. As anexample, heat exchanger 100 may be used in refrigeration system 60 ofrefrigerator appliance 10 (FIG. 2). Heat exchanger 100 includes featuresfor improving performance of an associated refrigeration system or HVACsystem, as discussed in greater detail below.

As may be seen in FIG. 10, heat exchanger 100 defines an axial directionA and a radial direction R. Heat exchanger 100 includes a conduit 110.Conduit 110 is configured for containing a refrigerant therein anddirecting a flow of refrigerant therethrough. Conduit 110 has an outersurface 112. Conduit 110 may be constructed of or with any suitablematerial. As an example, conduit 110 may be constructed of or with ametal, such as copper tubing or aluminum tubing. Conduit 110 may alsohave any suitable cross-sectional shape. For example, conduit 110 mayhave a circular cross-section, e.g., in a plane that is perpendicular tothe axial direction A.

Heat exchanger 100 also includes a spine fin strip or assembly 120.Spine fin assembly 120 is disposed or positioned on or at outer surface112 of conduit 110. In particular, spine fin assembly 120 is wrappedabout conduit 110 such that spine fin assembly 120 is mounted to conduit110 at outer surface 112 of conduit 110. Thus, spine fin assembly 120may have a helical shape, e.g., when wound about conduit 110. Spine finassembly 120 includes a base 122, a plurality of first spine fins 124and a plurality of second spine fins 126. Base 122 is positioned onconduit 110 at outer surface 112 of conduit 110, and first spine fins124 and second spine fins 126 are mounted to base 122 and wound aboutconduit 110, e.g., such that first spine fins 124 extend along theradial direction R from base 122 and second spine fins 126 are bentrelative to first spine fins 124.

Spine fin assembly 120 may be constructed of or with any suitablematerial. As an example, spine fin assembly 120 may be constructed of orwith a metal, such as copper or aluminum. In particular, spine finassembly 120 may be constructed of or with a single, continuous sheet ofmaterial, such as a sheet of aluminum or copper. Thus, base 122, firstspine fins 124 and second spine fins 126 may be defined by or formedwith the single, continuous sheet of material.

As may be seen in FIG. 3, conduit 110 defines a length L, e.g., alongthe axial direction A. Base 122, first spine fins 124 and second spinefins 126 are wound about conduit 110 along the length L of conduit 110.Base 122, first spine fins 124 and second spine fins 126 may be wound atany suitable rate along the length L of conduit 110. For example, base122, first spine fins 124 and second spine fins 126 may be wound aboutconduit 110 at a rate of about nine windings per inch of conduit 110along the length L of conduit 110. As another example, base 122, firstspine fins 124 and second spine fins 126 may be wound about conduit 110at a rate of greater than seven windings per inch of conduit 110 alongthe length L of conduit 110 and less than eleven windings per inch ofconduit 110 along the length L of conduit 110.

Second spine fins 142 may also be distributed in any suitable manner onconduit 110 and/or base 131. For example, the spine fins of second spinefins 142 may be bent such that second spine fins 142 are distributed ina helical pattern (shown with arrows H) within and/or between windingsof spine fin assembly 120. Bending second spine fins 126 relative tofirst spine fins 124 (e.g., and distributing second spine fins 126 inthe helical pattern H) may assist with forming vortex generators onspine fin assembly 120. Without wishing to be bound to any particulartheory, the bent second spine fins 126 may enhance heat transfer of heatexchanger 100 with ambient air about heat exchanger 100 by creatingturbulent airflow about first spine fins 124 and/or directing theturbulent airflow into a wake region to reduce recirculation flow. Thus,an efficiently of a system associated with heat exchanger 100 may beimproved.

It should be understood that second spine fins 126 need not be bent at ajunction between second spine fins 126 and base 122 in certain exemplaryembodiments. For example, second spine fins 126 may be bent such thatone portion of each spine fin of second spine fins 126 extends theradial direction R from base 122 and another portion (i.e., a winglet)of each spine fin of second spine fins 126 is bent relative to firstspine fins 124. Thus, second spine fins 126 may be bent away from base122 in certain exemplary embodiments to form vortex generators.

FIGS. 3, 4, 5, 6, 7, 8 and 9 illustrate a spine fin assembly 130 (FIG.9) according to an exemplary embodiment of the present subject matter invarious stages of formation. Any suitable spine fin assembly may beformed utilizing the steps outlined below. For example, spine finassembly 120 (FIG. 10) may be formed in the manner described below.

As may be seen in FIG. 3, a sheet of material 132 is provided. The sheetof material 132 may be any suitable material. For example, sheet ofmaterial 132 may be a metal, such as copper or aluminum. The sheet ofmaterial 132 has a first side portion 134 and a second side portion 136positioned opposite each other on the sheet of material 132.

Turning now to FIG. 4, the sheet of material 132 is cut. In particular,the sheet of material 132 is cut such that a set of spine fins 138 iscut at first side portion 134 of the sheet of material 132 and at secondside portion 136 of the sheet of material 132 with a base 131 positionedbetween the spine fins 138 at first and second sides 134, 136 of thesheet of material 132. The sheet of material 132 may be cut such thatspine fins 138 at first side portion 134 of the sheet of material 132are aligned with spine fins 138 at second side portion 136 of the sheetof material 132. For example, each cut at the first side portion 134 ofthe sheet of material 132 may be aligned with a respective cut at thesecond side portion 136 of the sheet of material 132.

Turning now to FIGS. 5 and 6, a subset of spine fins 138 are bent. Thus,a set of first spine fins 140 may remain straight or unbent and a set ofsecond spine fins 142 may be bent relative to the first spine fins 140.Any suitable method or mechanism may be used to bend the second spinefins 142. For example, combs 150 at first and second side portions 134,136 may include teeth 152 that are spaced apart from one another. Teeth152 of combs 150 may be urged or pressed against second spine fins 142in order to bend second spine fins 142 while first spine fins 140 passbetween teeth 152 of combs 150. Thus, gaps between teeth 152 of combs150 may be selected correspond to a desired number of first spine fins140 between each pair of second spine fins 142.

Second spine fins 142 at first side portion 134 of the sheet of material132 may be offset from second spine fins 142 at second side portion 136of the sheet of material 132. For example, each second spine fin 142 atfirst side portion 134 of the sheet of material 132 may be positionedbetween a respective pair of second spine fins 142 at second sideportion 136 of the sheet of material 132. The selection of the gapsbetween teeth 152 of combs 150 and/or the positioned of teeth 152 ofcombs at first and second side portion 134, 136 of the sheet of material132 may assist with positioning second spine fins 142 in a desiredpattern, as discussed in greater detail below.

As shown in FIG. 7, second spine fins 142 at first side portion 134 ofthe sheet of material 132 may be bent opposite second spine fins 142 atsecond side portion 136 of the sheet of material 132. In particular,second spine fins 142 at first side portion 134 of the sheet of material132 may extend from a first surface of the sheet of material 132, andsecond spine fins 142 at second side portion 136 of the sheet ofmaterial 132 may extend from a second, opposite surface of the sheet ofmaterial 132. Thus, combs 150 may move in opposite directions duringbending of second spine fins 142 at first and second side portion 134,136 of the sheet of material 132.

Turning now to FIGS. 7 and 8, the sheet of material 132 is folded at aset of folds 144, e.g., into a U-shape. Thus, the sheet of material 132may folded at folds 144 such that spine fins 138 at first side portion134 of the sheet of material 132 are spaced apart from spine fins 138 atsecond side portion 136 of the sheet of material 132 with base 131. Asshown in FIG. 8, first spine fins 140 may extend perpendicularly frombase 131 and second spine fins 142 may be angled relative to first spinefins 140 after folding the sheet of material 132 at set of folds 144.Turning now to FIG. 9, spine fin assembly 130 is formed and may bewrapped about a conduit to assemble a heat exchanger. For example,turning to FIG. 10, spine fin assembly 130 may be wrapped onto an outersurface 112 of conduit 110 in order to form heat exchanger 100.

As discussed above, second spine fins 142 are bent relative to firstspine fins 140. In particular, each spine fin of first spine fins 140defines an angle, a, with outer surface 112 of conduit 110 (e.g., orbase 131) proximate first spine fins 140. The angle α may be aboutninety degrees. As used herein, the term “about” means within tendegrees of the stated angle when used in the context of angles.Conversely, each spine fin of second spine fins 142 defines an angle, β,with outer surface 112 of conduit 110 (e.g., or base 131) proximatesecond spine fins 142. The angle β may be no greater than seventydegrees. As another example, the angle β may be about forty-fivedegrees.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they include structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal languages of the claims.

What is claimed is:
 1. A method for forming a heat exchanger,comprising: cutting a plurality of spine fins into a sheet of metal;bending a subset of the plurality of spine fins; folding the sheet ofmetal to form a spine fin strip such that the plurality of spine finsextend from a base of the spine fin strip; and wrapping the spine finstrip onto a conduit in a helical pattern at an outer surface of theconduit such that the plurality of spine fins includes spine fins thatextend radially away from the outer surface of the conduit and alsoincludes spine fins that are bent relative to the radially extendingspine fins.
 2. The method of claim 1, wherein said step of bendingcomprises utilizing a comb to bend the subset of the plurality of spinefins at said step of bending, the comb comprising a plurality of tinesthat are spaced apart from one another.
 3. The method of claim 1,wherein the subset of the plurality of spine fins are bent such that thesubset of the plurality of spine fins form vortex generators on thespine fin strip after said step of wrapping.
 4. The method of claim 1,wherein each spine fin of the subset of the plurality of spine finsdefines an angle, β, with the outer surface of the conduit proximate thesubset of the plurality of spine fins after said step of wrapping, βbeing no greater than seventy degrees.
 5. The method of claim 1, whereinthe spine fins of the second plurality of spine fins are bent such thatthe spine fins of the second plurality of spine fins are distributed ina helical pattern between windings of the spine fin strip after saidstep of wrapping.
 6. The method of claim 1, wherein the conduitcomprises aluminum.
 7. The method of claim 1, wherein the sheet of metalcomprises aluminum.
 8. A heat exchanger, comprising: a conduit having anouter surface; a spine fin strip wrapped onto the conduit in a helicalpattern at the outer surface of the conduit, the spine fin stripcomprising a base positioned at the outer surface of the conduit; afirst plurality of spine fins extending radially from the base and awayfrom the outer surface of the conduit; and a second plurality of spinefins bent relative to the spine fins of the first plurality of spinefins; wherein the base, the spine fins of the first plurality of spinefins and the spine fins of the first plurality of spine fins are formedfrom a common piece of sheet metal.
 9. The heat exchanger of claim 8,wherein each spine fin of the first plurality of spine fins defines anangle, a, with the outer surface of the conduit proximate the firstplurality of spine fins, a being about ninety degrees, each spine fin ofthe second plurality of spine fins defining an angle, β, with the outersurface of the conduit proximate the second plurality of spine fins, βbeing no greater than seventy degrees.
 10. The heat exchanger of claim8, wherein the spine fins of the second plurality of spine fins are bentsuch that the spine fins of the second plurality of spine fins aredistributed in a helical pattern between windings of the spine finstrip.
 11. The heat exchanger of claim 8, wherein the spine fins of thesecond plurality of spine fins are bent such that the spine fins of thesecond plurality of spine fins form vortex generators on the spine finstrip.
 12. The heat exchanger of claim 8, wherein the conduit comprisesaluminum.
 13. The heat exchanger of claim 8, wherein the sheet metalcomprises aluminum.
 14. A heat exchanger, comprising: a conduit havingan outer surface; a spine fin strip wrapped onto the conduit in ahelical pattern at the outer surface of the conduit, the spine fin stripcomprising a base positioned at the outer surface of the conduit; afirst plurality of spine fins mounted to the base, each spine fin of thefirst plurality of spine fins defining an angle, a, with the outersurface of the conduit proximate the first plurality of spine fins, abeing about ninety degrees; and a second plurality of spine fins mountedto the base, each spine fin of the second plurality of spine finsdefining an angle, β, with the outer surface of the conduit proximatethe second plurality of spine fins, β being no greater than seventydegrees; wherein the base, the spine fins of the first plurality ofspine fins and the spine fins of the first plurality of spine fins areformed from a common piece of sheet metal.
 15. The heat exchanger ofclaim 14, wherein the spine fins of the second plurality of spine finsare distributed in a helical pattern between windings of the spine finstrip.
 16. The heat exchanger of claim 14, wherein the spine fins of thesecond plurality of spine fins form vortex generators on the spine finstrip.
 17. The heat exchanger of claim 14, wherein the conduit comprisesaluminum.
 18. The heat exchanger of claim 14, wherein the sheet metalcomprises aluminum.